It is possible to find the relationship between the mass and the radius of a spherical black hole keeping in mind that the maximum speed that could reach an object, according to the theory of relativity, it is the speed of light.

The scape velocity in the surface of a spherical star will be the maximum velocity that could reach an object in order to stay in orbit around the star. This will happen when the kinetic energy of one object is equal to the potential energy due to the star gravitational attraction. Continue reading →

It is said that the gravitational waves are a consequence of the theory of relativity, of Albert Einstein, but it is difficult to find texts in which they argue why this relationship, except that they are arising from the study of the Einstein field equations. Let’s try to apply a little logic and some knowledge of relativity in this issue.

The key question is the following question: is possible to convey the effect of gravity faster than light?

Let’s assume for a moment that that is possible. For simplicity suppose that gravity affects instantaneously, or at infinite speed. That has a very important consequence, that is that you could create an experiment to transmit information instantaneously through instantaneous changes of gravitational effects. …more about gravitational waves